I usually start picking mine in the fall and harvest the last ones before the first freeze. Mine are outdoor plants though. If yours are container grown then it will depend on when they flowered and set fruit. Meyers will typically get quite a bit larger than "grocery" store sized lemons also. How are yours grown?

when I got my meyer last april it had set fruit and they ripened in november.

Harvested mine inside in March. I think most of fruit came from blossums that came out after taking the tree outside. So far this year I have 3 fruit set indoors during the spring.